The overall objectives of this grant are to determine the effect of cell surface alterations on the immunologic behavior of cells. Certain substances all appear to increase cell immunogenicity in appropriate doses so that many studies have involved the design of model systems for tumor immunotherapy using such altered tumor cells. In recent years, attention has turned less and less to the design of model systems for tumor immunotherapy than to the investigation of the mechanisms of the beneficial effects of tumor immunotherapy using active specific methods of immunization in vitro. Attention has particularly turned toward investigation of how these and other substances interact with cells and alter cellular behavior in vitro. BIBLIOGRAPHIC REFERENCES: Ferguson, R.M., Schmidtke, J.R., and Simmons, R.L.: Immunotherapy of experimental animals, in I. Green, S. Cohen and R.T. McCluskey (eds.), Mechanisms of Tumor Immunity. New York, John Wiley & Sons, Inc., 1977, pp. 193-214. Anderson, S.M., Ferguson, R.M., and Simmons, R.L.: Functional characterization of in vitro generated suppressor cells. Fed. Proc., 36:1269, 1977.